<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <script src="./demo14.js"></script>
</head>
<body>
     <form action="" method="get">
        <input id="username" type="text" name="username" value="" placeholder="请输入用户名" /><br/>
        <input id="password" type="password" name="password" placeholder="请输入密码" /><br>
        <button type="button">提交</button>
    </form>
</body>
</html>